Support is requested for the establishment of a Hypertension Center for the longitudinal analysis and treatment of hypertensive diseases based on specific biochemical profiles. Recent developments make it possible to classify the large population of so-called "essential" hypertension on the basis of defineable abnormalities in the hormones of the renin-angiotensin-aldosterone system. This is accomplished by separating patients first in terms of abnormalities in renin secretion and then by further subdivision according to variations in their adrenal cortical secretions. Basically our proposal is to classify hypertensive patients on the basis of an initial detailed metabolic ward study program. With this information in hand, longitudinal follow-up may define differences in natural history and new prognostic values. Furthermore, we will take advantage of the known benefits of antihypertensive drug therapy and apply the additional and new approach of utilizing antihypertensive drugs with known effects on the predetermined abnormalities of the renin-angiotensin-aldosterone system. Specific pharmacological correction of hormonal deviations could prove to be a real advantage in therapy. Past experience suggests that it will be possible to define new hormonal mechanisms in the hypertensive population and then to develop new and more specific treatments. This approach also promises to define more specifically the natural history and prognostic implications of the different biochemical and physiologic abnormal patterns. Parallel studies in animal models and of other relevant human disorders will support the clinical observations and physiologic studies.